SOLVED Difficulty With Minecraft Server

This is another "cant' set up a Minecraft server" post ... Hoping someone will be able to help. The server is working on my computer but not on his.

Both of our computers are wired directly to the ASUS the RT-AC86U router with an ethernet cable. His IP address for local use is 192.168.50.166.

These are the settings for port forwarding:

Service Name: Minecraft Source IP (blank). Port Range: 2565 Local IP: 192.168.50.166 Port: 25565 TCP : BOTH

He connects to 192.168.50.166 when he runs Minecraft from his own computer. However, if he enters the external IP (obtained via the "Network Map" page of the router settings), it yields the error:

Failed to connect to the server io.netty.channel.AbstractChannel$AnnotatedConnectException: Connection timed out: no further information

When I attempt to connect my computer to 192.168.50.166, I get the exact same error message from Minecraft.

But here's the kicker ... Everything works if I run the server on my personal computer (192.168.50.48), and change the Local IP port forward settings accordingly. Yurock I can connect to the Minecraft server using either my local IP or with the external IP.